1. Field of the Invention
The present invention relates to a process for producing an aqueous emulsion. More precisely, the present invention relates to a process for producing an aqueous emulsion, said process allowing to produce an aqueous ethylene-vinyl acetate copolymer emulsion having an extremely high solid concentration, and said process enabling suppression of increase in viscosity of the reaction system during copolymerization reaction and formation of a stable emulsion.
2. Prior Art
Aqueous ethylene-vinyl acetate copolymer emulsions have found wide applications in the field of adhesive. From the viewpoint of drying efficacy, it is required that aqueous emulsions for adhesive have a high solid concentration. When aqueous ethylene-vinyl acetate copolymer emulsions with high solid content were produced according to conventional processes, however, there was a problem that the viscosity in the reaction system increased during copolymerization reaction, resulting in difficulty in stable completion of the desired copolymerization reaction due to insufficient stirring or insufficient removal of heat of reaction.
The present inventors have extensively studied for a process for producing an aqueous ethylene-vinyl acetate copolymer emulsion having no such problems, and found that an aqueous emulsion having a high solid cotent can be stably produced by adding vinyl acetate and a polyvinyl alcohol as an emulsifying dispersant to the copolymerization system in divided portions so that the increase in viscosity is suppressed. The present invention has been completed